fix: correct gallery asset paths and update fetch URL

admin/index.html

@@ -241,6 +241,6 @@
         </div>
     </div>
 
-    <script src="/build/admin.js" defer></script>
+    <script src="/public/build/admin.js" defer></script>
 </body>
 </html>

gallery/index.html

@@ -179,6 +179,6 @@
     </script>
     <script src="../script.js" defer></script>
     <script src="../update.js" defer></script>
-    <script src="/build/gallery.js" defer></script>
+    <script src="/public/build/gallery.js" defer></script>
 </body>
 </html>

update.js

@@ -35,7 +35,7 @@ document.addEventListener('DOMContentLoaded', () => {
         }
     }
 
-    fetch('update.json')
+    fetch('/update.json')
         .then(response => response.json())
         .then(data => {
             const update = data[0];